Light-electricity-microorganism composite system for synchronously repairing micropollutants in high-transparency water body-sediment two phases and application of light-electricity-microorganism composite system

Abstract

The invention discloses a light-electricity-microorganism composite system for synchronously repairing micropollutants in a high-transparency water body-sediment two phase and application of the light-electricity-microorganism composite system, and relates to the technical field of water treatment and ecological restoration. The invention designs a light-electricity-microorganism composite system. A specific solid-liquid interface of a high-transparency water body-sediment composite system is matched with a microbial fuel cell; meanwhile, a piezoelectric high-molecular polymer and perovskite are compounded to serve as a cathode for the first time, and a piezoelectric electro-catalytic material and a semi-artificial photosynthesis are introduced to an anode to strengthen the oxidation-reduction process of the system, so that a novel optical-electric-microbial fuel cell model is constructed; the pollutant reduction efficiency of the sediment-overlying water compound system is enhanced, and the purposes of energy conservation and cyclic utilization are achieved.

Description

Technical Field

[0001] The present invention relates to the field of water treatment technology and ecological restoration technology, and in particular to a light-electricity-microorganism composite system for synchronously repairing micropollutants in high-transparency water-sediment two phases and applications thereof. Background Art

[0002] The solid-liquid system refers to a complex ecosystem composed of a sediment layer at the bottom of the sea or river and a water layer covering the sediment layer (i.e., the overlying water layer). Sediments are mainly composed of solid particles that settle to the bottom of the water body. These particles are usually insoluble in water and may contain various minerals, organic matter, microorganisms, etc. The overlying water layer is the water layer covering the sediment, and its thickness may vary depending on factors such as geographical location, water depth, and water flow speed.

[0003] The overlying water layer and the sediment layer are closely connected through material exchange and energy flow. By deeply understanding the structure and function of this system, we can better understand the evolution of the water environment, predict and evaluate the impact of human activities on the water environment, and formulate effective environmental protection and governance strategies. In addition, this system also has broad application prospects in the fields of wastewater treatment and ecological restoration.

[0004] Piezoelectric photocatalysis is a new type of energy conversion technology that combines the piezoelectric effect with photocatalytic reactions to achieve the process of converting mechanical energy and light energy into electrical energy, thereby driving chemical reactions. In the piezoelectric photocatalytic process, photocatalysts are combined with piezoelectric materials to form piezoelectric photocatalytic composite materials. When this composite material is subjected to the combined effects of light and mechanical stress, the electric field generated by the piezoelectric effect enhances the light absorption and charge separation efficiency of the photocatalyst, thereby accelerating the rate of the chemical reaction.

[0005] Semi-artificial photosynthesis is a biocatalytic process driven by a material-organism hybrid system, which cleverly combines efficient light energy capture materials with highly selective biocatalytic mechanisms, aiming to achieve high-efficiency and high-specificity conversion of light energy to chemical energy. The main composite methods include natural light as a light absorber combined with nanomaterials, and materials as light absorbers combined with enzymes or microbial whole-cell catalysts.

[0006] Microbial fuel cells are an innovative technology that integrates energy production and wastewater purification. They cleverly use microorganisms as biocatalysts to oxidize organic and inorganic substances while generating electricity. Compared with traditional wastewater treatment processes, microbial fuel cells have the advantages of no secondary pollution problems and no need for aeration facilities. In the microbial fuel cell system, microorganisms catalyze the decomposition of organic matter in sewage in the anaerobic anode area to produce protons and electrons. Protons reach the cathode through a specific transmission mechanism, while electrons are transferred to the cathode through an external circuit. The protons and electrons in the cathode combine with external electron acceptors to complete the closure of the electron transport chain, achieve efficient sewage purification, and recycle energy.

[0007] At present, the problem of water and sediment complex pollution in solid-liquid systems, especially the problem of micropollutants in high-transparency water, has become an important problem in the field of environmental governance. In this regard, the inventor believes that there is no relevant research on coupling light-electricity with microbial fuel cells to enhance the treatment of solid-liquid phases of high-transparency water-sediment. Therefore, how to solve the above technical problems is a technical problem currently faced by general technicians in this field.

[0008] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0009] In response to the above technical problems, an embodiment of the present invention provides a light-electricity-microorganism composite system for synchronously repairing micropollutants in high-transparency water and sediment phases and its application to solve the problems raised in the above background technology.

[0010] A photo-electric-microorganism composite system, comprising: an anode, a cathode, an external resistor, an underwater light source and an electroactive bacteria / FeS hybrid material;

[0011] The lower end of the anode is inserted into the sediment layer and the upper end thereof extends to the overlying water layer; the C-BiOBr / MXene material is in-situ grown at the position where the anode is exposed in the overlying water layer;

[0012] The cathode floats on the overlying water layer; the cathode is a piezoelectric photocatalytic film PVDF-HFP, on which La 1-x Ca x NiO 3 ;

[0013] The external resistor is connected to the anode and the cathode via a first wire;

[0014] The underwater light source is set in the overlying water layer;

[0015] The electroactive bacteria / FeS hybrid material is added into the sediment layer; the electroactive bacteria / FeS hybrid material includes electroactive bacteria and FeS.

[0016] Preferably, it also includes a solar panel; the solar panel is externally arranged above the overlying water layer, and is used to provide electrical energy for the underwater light source.

[0017] Preferably, the wavelength of the underwater light source is >300nm, and the power of the underwater light source is <60W.

[0018] Preferably, the main body material of the anode is iron wire.

[0019] Preferably, the C-BiOBr / MXene material includes a highly conductive two-dimensional material MXene and BiOBr; the highly conductive two-dimensional material MXene and BiOB are compounded together by electrostatic adsorption; and the surface of BiOBr is modified by CND.

[0020] Preferably, the anode comprises a plurality of anodes, and the plurality of anodes are connected in series; stones are wound between adjacent anodes.

[0021] Preferably, the piezoelectric photocatalytic film PVDF-HFP is a porous electrode film made of a flexible polymer material polyvinylidene fluoride-hexafluoropropylene copolymer.

[0022] Preferably, the piezoelectric photocatalytic film PVDF-HFP is composed of a crystalline part of polyvinylidene fluoride and an amorphous part of hexafluoropropylene.

[0023] Preferably, the electroactive bacterium is Shewanella.

[0024] An application of the above-mentioned photo-electric-microorganism composite system in water ecological restoration projects.

[0025] The embodiment of the present invention provides a light-electricity-microorganism composite system for synchronously repairing micropollutants in high-transparency water-sediment phases and its application, which has the following beneficial effects:

[0026] 1. The present invention constructs a light-electricity-microorganism composite system, which combines the mechanical energy generated by the flow of sewage and the light energy supplied under natural light conditions, and uses electroactive microorganisms mainly composed of Shewanella to synergistically enhance the efficiency of pollution treatment in the solid-liquid two-phase;

[0027] 2. Compared with other processes, the present invention introduces a microbial fuel cell system and a nanomaterial photo-electrocatalytic enhanced oxidation-reduction process, which reduces the problem of excessive thickness of the anode biofilm in the fuel cell and the high resistance in the transmission process affecting the electron mass transfer, and accelerates the removal efficiency of solid-liquid two-phase composite pollution;

[0028] 3. The present invention designs multiple series connections in the anode electrode part, and the number range of anodes can be adjusted according to the region and the size of the pollution range, or the thickness and size of the cathode electrode can be flexibly adjusted to reduce equipment costs and ensure the recycling of resources;

[0029] 4. The light-electricity-microorganism composite system designed by the present invention is easy to build, easy to recycle, easy to handle, and has high applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the light-electricity-microorganism composite system of the present invention;

[0031] Figure 2 A top view of the light-electricity-microorganism composite system of the present invention;

[0032] Figure 3 It is a left view of the light-electricity-microorganism composite system of the present invention;

[0033] In the figure, 1-solar panel; 2-cathode; 3-first wire; 4-second wire; 5-resistance; 6-C-BiOBr / MXene material; 7-main material; 8-sediment layer; 9-electroactive bacteria / FeS hybrid material; 10-underwater light source; 11-stone. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0035] In response to the above technical problems, an embodiment of the present invention provides a light-electricity-microorganism composite system for synchronously repairing micropollutants in high-transparency water and sediment phases and its application to solve the problems raised in the above background technology.

[0036] A photo-electric-microorganism composite system, comprising: an anode 6, a cathode 2, an external resistor 5, an underwater light source 10 and an electroactive bacteria / FeS hybrid material 9;

[0037] The lower end of the anode 6 is inserted into the sediment layer 8 and the upper end thereof extends to the overlying water layer; the lower end of the anode 6 is inserted into the sediment layer 8, which is not only used to fix the anode 6, but also the lower end of the anode 6 is deeply buried in the sediment layer 8, which can provide an attachment point for the growth and reproduction of microorganisms;

[0038] The anode 6 is exposed to the overlying water layer where C-BiOBr / MXene material is grown in situ;

[0039] The cathode 2 floats on the overlying water layer; the cathode 2 is a piezoelectric photocatalytic film PVDF-HFP, on which a perovskite metal oxide (La 1-x Ca x NiO 3 );

[0040] The external resistor 5 is connected to the anode 6 and the cathode 2 via the first wire 3;

[0041] The underwater light source 10 is disposed in the overlying water layer;

[0042] The electroactive bacteria / FeS hybrid material 9 is added into the sediment layer 8; the electroactive bacteria / FeS hybrid material 9 comprises electroactive bacteria and FeS; the electroactive bacteria is preferably Shewanella.

[0043] Among them, electroactive bacteria metabolize carbon sources under anaerobic conditions to produce hydrogen sulfide gas, which reacts with pyrite and self-assembles into a semi-artificial photosynthesis system.

[0044] The C-BiOBr / MXene material on the anode 6, when subjected to the pressure of the mechanical energy generated by the water flow, will undergo lattice deformation, which can accelerate the photocatalytic removal of pollutants and synergistically reduce heavy metal (Zn, Cu) ions, etc., thereby reducing the toxicity of heavy metals.

[0045] La is loaded on the piezoelectric photocatalytic film PVDF-HFP of cathode 2 1-x Ca x NiO 3 The doped cathode exhibits metallic conductivity and is placed at the cathode as the main catalyst for reduction reaction.

[0046] After receiving the underwater light source on the surface of the sediment layer 8, some electroactive bacteria / FeS hybrid materials stimulate the separation of electron-hole pairs and generate active groups to participate in the degradation of pollutants at the solid-liquid interface; the electroactive bacteria quickly transfer electrons in FeS to the surface of the anode 6 through a special extracellular electron transfer mechanism.

[0047] In this embodiment, a solar panel 1 is further included; the solar panel 1 is externally placed above the overlying water layer, and is used to provide electric energy for the underwater light source 10; the solar panel 1 is electrically connected to the underwater light source 10 through a second wire 4. The solar panel 1 is configured to collect natural light and provide electric energy for the underwater light source 10. The size of the solar panel 1 is preferably 50 cm×50 cm.

[0048] In this embodiment, the wavelength of the underwater light source 10 is >300nm, and the power of the underwater light source 10 is <60W; wherein, the wavelength of the light source >300nm belongs to the visible light range, and the power <60W is equivalent to the size of a halogen bulb.

[0049] In this embodiment, the main material 7 of the anode 6 is iron wire; the iron wire can be made into a rice ear shape.

[0050] In this embodiment, the C-BiOBr / MXene material includes a highly conductive two-dimensional material MXene and bismuth oxybromide (BiOBr); the highly conductive two-dimensional material MXene and BiOB are compounded together by electrostatic adsorption; the surface of BiOBr is modified by carbon nanodots (CND). The C-BiOBr / MXene material has piezoelectric photocatalysis.

[0051] In the present embodiment, the anode 6 includes a plurality of anodes 6 connected in series; specifically, the number of anodes 6 can be set according to the difference in regional area, and the anode 6 can be detachably fixed and plugged into the sediment layer 8. The detachable and fixed loading and unloading facilitates the replacement and recycling of the anode 6.

[0052] Stones 11 are wound between adjacent anodes 6 . The purpose of winding the stones 11 between adjacent anodes 6 is to stabilize the height of the anodes 6 in the transverse direction and to extend the depth of the sediment layer 8 in the longitudinal direction.

[0053] In this embodiment, the piezoelectric photocatalytic film PVDF-HFP is a porous electrode film made of a flexible polymer material polyvinylidene fluoride-hexafluoropropylene copolymer.

[0054] In this embodiment, the piezoelectric photocatalytic film PVDF-HFP is composed of a crystalline part of polyvinylidene fluoride (PVDF) and an amorphous part of hexafluoropropylene (HFP). The piezoelectric photocatalytic film PVDF-HFP combines the excellent chemical stability of HFP and vinylidene fluoride (VDF) with the flexibility and good processing performance of HFP, and can sway gently with the water flow.

[0055] It should be noted that the specific working principle of the light-electricity-microorganism composite system designed by the present invention is as follows:

[0056] C-BiOBr / MXene material is in-situ grown on the position where the anode 6 electrode is exposed to the overlying water layer. After being subjected to the mechanical energy of the water flow, strain pressure will occur on the surface of the material, and the lattice deformation of the semiconductor is further converted into chemical energy; it can accelerate the photocatalytic removal of pollutants and synergistically reduce heavy metal (Zn, Cu) ions, etc., to reduce the toxicity of heavy metals.

[0057] In the C-BiOBr / MXene material, the piezoelectric BiOBr is modified by positively charged ions on the CND surface. The electrostatic adsorption between the materials makes the highly conductive two-dimensional material MXene with a negative surface tightly combined with it, making it stable and not easy to decompose.

[0058] When natural light is refracted and illuminated by the underwater light source 10 on the surface of the C-BiOBr / MXene material, it stimulates the separation of semiconductor electron and hole pairs, and the holes undergo oxidation reactions in the underwater environment to generate hydroxyl radicals, which participate in the degradation of organic pollutants in the overlying water layer. Organic pollutants can be decomposed into different intermediate products, providing carbon sources for the growth and metabolism of microorganisms on the sediment surface and the bottom of the anode 6, and then continue to mineralize into the final products of carbon dioxide and water.

[0059] The entire main body of the anode 6 is supported by an iron wire, which sways gently with the flow of overlying water and is not easily broken. The C-BiOBr / MXene material is loaded onto the surface of the iron wire through an in-situ growth method, which is stable and strong and suitable for multiple cycles.

[0060] The anode 6 extends downward to the bottom of the sediment, providing a growth and incubation attachment point for the bottom community of mainly electroactive microorganisms, and strengthening the proliferation of the biofilm at the bottom of the anode 6. Electroactive bacteria / FeS hybrid material 9 is added to the sediment layer 8. The low electron transfer efficiency caused by the excessively thick biofilm at the bottom of the anode, as well as the high recombination efficiency and low photon efficiency of the photogenerated electron-hole pairs existing in single photocatalysis can be changed by using conductive nanomaterials such as FeS.

[0061] Then, the unique extracellular electron transfer pathway of electroactive bacteria is used to transfer electrons to the metal surface of the main material 7, and then to the anode 6 to participate in the electronic circuit. Due to the growth of microorganisms, part of the electroactive bacteria / FeS hybrid material 9 is exposed to the surface of the sediment layer 8, and is illuminated by the external natural light and the underwater light source 10. FeS excites photogenerated carriers under the action of light, and generates active free radicals to participate in the degradation process of pollutants at the solid-liquid interface. The underwater light source 10 strengthens the light intensity of the overlying water bottom due to the refraction loss of sunlight, and accelerates the removal of pollutants.

[0062] Cathode 2 is made of high-performance polymer materials such as PVDF-HFP as the main framework and doped with La 1-x Ca x NiO 3 Composite materials are formed; the structural design of this composite material can adjust the electronic structure, carrier concentration and oxygen vacancies of the material, thereby optimizing the performance of the material. 1-x Ca x NiO 3Absorb light energy and generate photogenerated electrons and holes. These photogenerated carriers migrate to the surface of the composite material on the cathode 2 and undergo redox reactions with the pollutant molecules adsorbed on the surface, thereby removing them. The introduction of PVDF is used to improve the surface properties of the material, increase the separation efficiency of photogenerated carriers, and enhance the piezoelectric catalytic performance. As the cathode 2, this part mainly undergoes reduction reactions. During the electrolysis of water, the composite material can catalyze the decomposition of water molecules to produce hydrogen and oxygen, while removing pollutants in the water.

[0063] During the flow of sewage in natural water bodies, the cathode 2 is driven to convert mechanical energy in the natural body into chemical energy. Organic matter is decomposed to produce electrons and protons. The electrons are received by the anode 6 and transmitted to the cathode through the wire and the resistor to form a loop. The irregular movement of the protons in the overlying water reaches the cathode and reacts with the electrons and the oxygen contained in the overlying water to generate CO. 2 and H 2 O and generate electric current, thus enhancing the treatment efficiency of solid-liquid two-phase composite pollutants. In sediment layer 8, the extracellular electron transfer, electrical conduction, and piezoelectric photocatalytic degradation of pollutants between electroactive microorganisms and FeS provide intermediate products for their digestion and metabolism process, reducing the overall residual toxicity of pollutants in the solid-liquid system and improving the mineralization degree of pollutants, producing CO 2 and H 2 O.

[0064] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A light-electricity-microorganism composite system, characterized in that: include: Anode, cathode, external resistor, underwater light source and electroactive bacteria / FeS hybrid material; The lower end of the anode is inserted into the sediment layer and the upper end thereof extends to the overlying water layer; the C-BiOBr / MXene material is in-situ grown at the position where the anode is exposed in the overlying water layer; The cathode floats on the overlying water layer; the cathode is a piezoelectric photocatalytic film PVDF-HFP, on which La 1-x Ca x NiO3; The external resistor is connected to the anode and the cathode via a first wire; The underwater light source is set in the overlying water layer; The electroactive bacteria / FeS hybrid material is added into the sediment layer; the electroactive bacteria / FeS hybrid material includes electroactive bacteria and FeS.

2. The light-electricity-microorganism composite system according to claim 1, characterized in that: Also included are solar panels; the solar panels are externally positioned above the overlying water layer, and the solar panels are used to provide electrical energy for the underwater light source.

3. The light-electricity-microorganism composite system according to claim 1, characterized in that: The wavelength of the underwater light source is >300nm, and the power of the underwater light source is <60W.

4. The light-electricity-microorganism composite system according to claim 1, characterized in that: The main material of the anode is iron wire.

5. The light-electricity-microorganism composite system according to claim 1, characterized in that: C-BiOBr / MXene material includes highly conductive two-dimensional materials MXene and BiOBr; highly conductive two-dimensional materials MXene and BiOB are compounded together through electrostatic adsorption; the surface of BiOBr is modified by CND.

6. The light-electricity-microorganism composite system according to claim 1, characterized in that: The anodes include a plurality of anodes, which are connected in series; and stones are wound between adjacent anodes.

7. The light-electricity-microorganism composite system according to claim 1, characterized in that: The piezoelectric photocatalytic film PVDF-HFP is a porous electrode film made of a flexible polymer material polyvinylidene fluoride-hexafluoropropylene copolymer.

8. The light-electricity-microorganism composite system according to claim 7, characterized in that: The piezoelectric photocatalytic film PVDF-HFP is composed of a crystalline part of polyvinylidene fluoride and an amorphous part of hexafluoropropylene.

9. The light-electricity-microorganism composite system according to claim 1, characterized in that: The electroactive bacteria are Shewanella spp.

10. Application of the photoelectric-microorganism composite system according to any one of claims 1 to 9 in a water ecological restoration project.

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